<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>JavaScript注释和结束符</title>
</head>

<body>
  <script>
    // alert弹出警示框
    alert('你好,js')
    // 单行注释
    /*块级注释*/
    alert('第二句话');

    // 一般在工作开发中，省略结束符

  </script>
</body>

</html>